1. Field of Invention
The present invention is related to a kind of paper clip which is unitarily made of a resilient sheet-steel and formed in U-shaped configuration through press punching process.
2. Description of the Prior Art
Paper clip is a device for clamping sheets of paper together. FIG. 1 illustrates a kind of paper clip which is commonly used at the present day and made of an iron wire through bending process. One disadvantage of this kind of paper clip is its weak clamping force. It can only clamp few sheets of paper at a time. As illustrated, a paper clip 2 of the prior art is comprised of an outer bend portion 22 and an inner bend portion 21. When in use, the inner bend portion 21 is bent upward relative to the outer bend portion 22 to define a "&gt;" shaped retaining space for the insertion therein of sheets of paper. Because the retaining space is substantially in a "&gt;" shape, the clamping force of the clip is stronger at its inner part and weaker at its outer part. Therefore, this kind of paper clip can not efficiently clamp more quantity of sheets of paper. Further, when the inner bend portion 21 and the outer bend portion 22 are bent to deviate from each other, they can not be resiliently turned to close back.
There is another type of clip made of resilient plastic material through punching process. As illustrated in FIG. 2, a plastic clip 3 is comprised of an outer loop portion 32 and an inner tongue portion 31. Similar to the paper clip 2 in FIG. 1, the inner tongue portion 31 and the outer loop portion 32 of the plastic clip 3 define therebetween a contained angle for clamping sheets of paper. The triangular space defined by the contained angle is gradually reduced inward. Therefore, the outer edge between the outer loop portion 32 and the inner tongue portion 31 provides relatively weaker clamping force for clamping sheets of paper, and sheets of paper that are clamped by a plastic clip of the kind may slip away easily.